Method for cooling the mold blocks of a casting machine with caterpillar mold

ABSTRACT

A method for cooling casting caterpillar mold blocks provides for a coolant spray case that has a rarefied atmosphere to prevent the escape of coolant. The apparatus to carry out the method has a casing, spray nozzles and connecting pipes and is connected to a source of rarefied pressure.

United States Patent [72] Inventor Wilhelm Friedrich Lauener Langenhard,Switzerland [21 Appl. No. 758,492

[22] Filed Sept. 9, 1968 [45] Patented Mar. 16, 1971 [73] AssigneeProlizenz AG Bahnhofstrasse, Chur, Switzerland [32] Priority Sept. 7,1967 [33] Switzerland [54] METHOD FOR COOLING THE MOLD BLOCKS OF ACASTING MACHINE WITH CATERPILLAR MOLD 8 Claims, 6 Drawing Figs.

[52] US. Cl. 164/87, 164/283 [51) Int. Cl B22d 11/06,

[50] Field of Search 164/60, 61,

87, 253, 279, 283' [56] References Cited UNITED STATES PATENTS 1,865,4437/1932 Perry et al. 164/87 2,560,639 7/1951 Giesler et al 164/283XFOREIGN PATENTS 594,346 3/1960 Canada 164/283 Primary Examiner-J.Spencer Overholser Assistant ExaminerR. Spencer Annear Attorney-ErnestF. Marmorek ABSTRACT: A method for cooling casting caterpillar moldblocks provides for a coolant spray case that has a rarefied atmosphereto prevent the escape of coolant. The apparatus to carry out the methodhas a casing, spray nozzles and connecting pipes and is connected to asource of rarefied pressure.

3 Sheets-Sheet I Patented March 16, 19%

Fig. 7

,Patented ml. 16, 171 I 3,570,583

3 Sheets-Sheet 5 The invention relates to a method and to a device forcooling the mold blocks of a casting machine with a caterpillar mold,especially of a machine for the casting of strips of nonferrous metals,chiefly of aluminum and aluminum alloys.

Reference is had to my copending application Ser. No 758,270, filed onthe same day as the instant application.

Several machines have been developed for the continuous casting ofstrips. In one machine the mold cavity is defined by a cooperating pairof endless chains of articulated mold blocks, and means are provided forrevolving each of said chains about its own center. The chains aremounted so that over a portion of their lengths they are in engagementone with the other and define between them a mold cavity having wallswhich move continuously as the respective chains are revolved togetherat the same linear speed. Machines of this kind have been named machineswith caterpillar molds. In one of the said machines the mold blocks ofone row are not tied together; they are moved separately in a guidesystem and maintained in circuit in such a way that they meet ever againat the pouring end of the mold cavity to form with the blocks of theother row a closed mold.

In the book I-Iandbuch des Stranggiessens of E. Herrmann, published 1958by the Aluminium-Verlag Gmbl-I in Dusseldorf (Western Germany), thecasting in caterpillar molds is described on pages 51 to 63.

Among the great number of proposed constructions only the machine of theHunter-Douglas Corporation used for the casting of strips from aluminumand aluminum alloys (Handbuch des Stranggiessens, pages 536/37 and540/41) has been successful. Hunter-Douglas machines are in operation inthe United States of America and in the Netherlands.

The Hunter-Douglas machine is characterized chiefly by the fact thateach mold block is cooled separately by water circu lation. The coolantis supplied thereto and withdrawn therefrom through rotatable coolantdistributors connected to the moving coolant passageways in the blocksby lengths of flexible hose. This cooling system is intricate and theHunter- Douglas machine is inaccessible on the side of the rotatinghoses.

It is also well known to eliminate the heat taken up by the mold blocksby dipping them into a cooling liquid or by sprinkling them after theypassed through the mold. This system of cooling has the advantage that aregulation of the temperature of the mold blocks is possible; that is tosay that these blocks can be brought by suitable cooling to the mostfavorable temperature for casting respectively for solidification of themelt, whereas mold blocks with constant inner cooling meet relativelycold at the entrance of the mold.

it is accordingly among the principal objects of the invention toprovide methods and means for the cooling of such molds without thedisadvantages of the prior art.

, It is a further object of the invention to provide for the coolantspraying of the mold blocks in a rarefied air to restrain the accidentalescape of coolant.

Further objects and advantages of the invention will be set forth inpart in the following specification and in part will be obvioustherefrom without being specifically referred to, the same beingrealized and attained as pointed out in the claims hereof.

According to the method of the invention the mold blocks of a castingmachine with caterpillar mold are cooled by spraying a coolant liquidagainst the mold blocks where their molding face is turned away from thecasting. The cooling liquid (generally water) is sprayed against theblocks in a case in which a reduced air pressure is maintained. Becauseof the air underpressure in the case respectively because of the inflowof air into the case caused by the underpressure, and an outflow ofcooling liquid out of the case between the same and the blocks and thepenetration of the liquid between the contact surface of the blocks isprevented. For instance, with vertical casting downwards the mold blocksare cooled. by sprinkling during their upward travel; they leave thezone of the cooling case quite dry, so that no disturbance can happendue to any residual coolant.

It has proved advantageous to add to the cooling liquid an emulsion ofoil in water or a lubricant suspension; the oil or other lubricantremaining in the mold blocks after evaporation of the coolant may besufficient for their lubrication.

The invention relates also to a device for carrying out the methodaccording to the invention. The device comprises substantially a case,preferably made of sheet metal, which is open towards the mold blocksand encloses a great number of spray nozzles for the coolant, forinstance several rows of spraying pipes, and is connected to a deviceproducing reduced pressure. The said device has to maintain thenecessary underpressure during cooling.

In the accompanying drawings;

FIG. 1 is a fragmentary perspective view, partly in section, of apreferred embodiment of the cooling case in cooperation with avertically disposed caterpillar mold;

FIG. 2 is a fragmentary sectional view taken along the line 11-11 ofFIG. 1;

FIG. 3 is a fragmentary elevational view seen in the direction of thearrow A of FIG. 1;

FIG. 4 is a schematic elevational view, partly in section, of anauxiliary unit for the operation of the cooling device according to FIG.1;

FIG. 5 is a fragmentary vertical sectional view of a modified uppercooling case of a caterpillar mold disposed horizontally; and

FIG. 6 is a fragmentary vertical sectional view of the lower coolingcase of the modification of FIG. 5.

In FIG. 1, a steel-sheet case 10 is open towards the blocks 11, whichmove upward in the present example, and reaches to the latter with aclearance as small as possible. Two vertical water supplying tubes 12are provided, the lower extremity of each of which is connected to apressure water-conduit 32. The water which rises in the tubes 12 flowsinto the horizontal spraying pipes 13 which are provided with nozzles l4through which water is sprayed against the molding face of the blocks11. A deflector 15 is disposed over each spray tube; the purpose of thesaid deflector is to prevent the pouring of a substantial amount ofwater down the walls of the mold blocks ll and its interference with thecooling by spraying. The bottom 16 of the case It) acts as a collectingvessel and is provided with an outlet tube l7.

By means of the tube 18 that is connected to a source of rarefiedpressure, such as an exhauster or a vacuum pump (not shown), a rarefiedpressure is produced in the case 10. The said tube is closed on itsupper end and is provided with boreholes 19 along its wall 9, and on theside away from the blocks, in order to avoid the entry of spray water,its bottom is connected to the source.

The air sucked out of the case enters the tube 18 through the lateralopenings 19; the lowest of them must, of course, be at such a level overthe bottom of the collecting vessel 16 that it cannot suck in water.Lateral sealing ledges 20 are provided, and a transversal sealing ledge21 at the upper part of the case; the latter reaches into the cavity ofthe mold blocks; a similar transversal sealing ledge 22 is fixed on thelower part of the case 10. The clearance between the surfaces of theblocks 11 and the sealing ledges 20, 21 and 22 amounts to several tenthsof a millimeter, for example to about 0.5 to 1 mm. This clearancedepends on the power of the device producing the rarefied pressure. Ararefied pressure of 200 to 300 millimeters water column produced by afan is quite sufficient under the above-mentioned conditions. in anyevent the pressure in the case 10 must be so low and the airflow throughthe clearance (indicated by arrows with white head in FIGS. 1 to 3) sopowerful that no water can escape through the clearance between thesealing ledges and the surface of the blocks. MOreover the outlet tube17 must be disposed in such a manner that it prevents the air fromentering the case 10.

An atmospheric excess pressure of 2m 10in the ascending pipes 12 for thecooling water is generally sufficient. The most favorable pressure maybe found most simply in each case by casting trials.

Angle irons 23 support the guide rolls 24, which touch laterally themold blocks 11. Two adjustable mounting frames 25 made from channelirons are connected to the structure which supports the casting machine.

The number of the spraying pipes 13 depends on their cooling effect andthe extent of the sprayed surface, on the available volume of coolingliquid and on the amount of heat which needs to be dissipated. In FIG. 1there are disposed about two spraying pipes for each mold block. Thesprayed surface is advantageously at least as large as the workingsurface (inner wall) of the mold which is in contact with the castingmetal prior to the separation of the solidifying casting from the moldwall. One needs at least dissipate approximately the whole heat taken upby the mold blocks during solidification.

FIG. 4 shows schematically an auxiliary unit utilizable for operatingthe cooling case according to FIG. 1. The said unit is in this view anintegral component of the cooling device, but this is not absolutelynecessary for carrying out the method of the invention. Nevertheless itoffers several advantages, for instance better starting conditions andthe possibility to add to the cooling water a die lubricant, forinstance an emulsion of oil in water, or a suspension of graphite. Thecooing water 26 flowing out from the cooling case flows through a cooler27 and a discharge pipe 28 into the coolant reservoir 29. From thelatter the coolant is supplied by ma means of a pump 30 driven by amotor 31 to the pressure water pipe 32, from which it flows through thespraying pipes 13; thereafter it is sprayed by the nozzles 14 againstthe working surfaces of the mold blocks 11 and collected on the bottomof the case 10; finally it flows again through the outlet tube 17 andthe discharge pipe into the coolant reservoir 29. The cooling waterremains in circulation; therefore, substantially only water lost byevaporation and, if a lubricant is used in the cooling water, onlylittle lubricant need to be replenished.

EXAMPLE 1000 mm. wide and 20 mm. thick bands of pure aluminum are castvertically downward in a machine with a caterpillar mold at a speed of2.5 meters per minute. The mold blocks made from forged steel have athickness of 250 mm. at the wide mold wall. The metal poured into themold has a temperature of 680 to 700 C., the emerging casting a surfacetemperature of 540 to 450 C. The cooling water is supplied with apressure of 6 kg. per square centimeter and sprayed on the mold blocksthrough ten spraying pipes. The speed of the circulating cooling wateramounts to 800 liters per minute; soon after the beginning of thecasting operation, the cooling water for the mold blocks has atemperature of about 30 C. at the inlet of the mold and of about 55 C.when flowing out through the outlet tube 17. Directly under the coolingcase the mold blocks have at their mold face a temperature of 170 to 200C. and when leaving the case a temperature of 60 to 70 C.

In the machine shown in FIGS. 1-4, the casting metal flows verticallydownward. The method and the device according to the invention, however,ma may instead be used also with casting upward as well as with castingin any other position.

When casting horizontally as well as in most positions of inclinedcasting, the cooling device must have, of course, a shape that differsfrom that of FIGS. l--3. FIGS. and 6 serve as examples. FIG. 5 showsschematically the upper and FIG. 6 the lower cooling device of acaterpillar casting machine disposed horizontally.

In FIG. 5, a case 33 is provided, made of sheet steel (corresponding tothe case of FIG. 1); and has on its interior a rarefied pressure. Thiscase 33 is connected through the tube 34 to an exhauster. It is providedat its whole periphery with sealing ledges 35 and reaches to the moldblocks 11 within 0.5

to 1 mm. The arrow B shows the travel direction of the mold blocks 11and therefore the casting direction. The case 33 is divided in twochambers 37 and-38 by a partition (intermediate bottom) 36. Sprayingpipes 39 are disposed in the chamber 37; they spray cooling waterthrough nozzles 40 against the mold blocks 11. Tubes 41 disposed throughthe partition 36 are welded to the .latter; they connect the chamber 37to the chamber 38. They are intended to remove by suction the coolingwater accumulating on the die halves or blocks and to conduct it intothe upper chamber 38, from which it flows out through the pipe 42. Forthis purpose the tubes 41 reach down nearly to the surface of the moldblocks and surmount the partition 36 up to the edge of the dischargepipe 42.

The tubes 41 have the further purpose of preventing the escape of waterbetween the mold blocks and the sealing ledges as well as through thejoint abutment between the mold blocks, by means of an intensive airflow.

The lower cooling device, which is represented in FIG. 6, does not needany partition. It comprises substantially a sheet case 43 with outlettube 44 for the water. The cooling water is sprayed by spraying pipes 45against the mold blocks ll and flows at the bottom of the case into theoutlet pipe 44. For the purpose of generating the air flow, which inthis device also has to prevent the escape of cooling water between themold blocks and the sealing ledges 46, a suction pipe 47 with apertures48 is disposed in the case 43 and is connected to a device I (not shown)producing rarefied pressure.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described, for obviousmodifications will occur to a person skilled in the art.

Having thus described the invention, what I claim as new and desire tobe secured by Letters Patent, is as follows.

I claim:

1. In a method for cooling, with the aid of a casing open at one side,the molding faces of mold blocks of a casting machine with a caterpillarmold, the steps comprising positioning the casing with the open sideclosely adjacent the molding faces where the molding faces are turnedaway from the casting, spraying through the open side a coolant againstthe molding faces while maintaining in the casing a rarefied airpressure such that due to the entry of air into the casing the coolantis restrained from escaping through any space between the casing and themold blocks.

2. A method according to claim I, the coolant containing an emulsion ofoil in water.

3. A device, for use in spray cooling the molding faces of a caterpillarmold having mold blocks, comprising a casing connected to a source ofrarefied air pressure and open towards the mold blocks and definingtherewith a clearance of several tenths of a millimeter, a conduit forsupplying a coolant, said casing containing several spraying nozzles fedfrom said conduit and directed against the molding faces.

4. A device according to claim 3 for the vertical continuous casting,comprising horizontal spraying pipes connected to said conduit anddisposed one above the other and having each several of said sprayingnozzles, a deflector disposed over each spraying pipe for drawing offthe water pouring down the wall of the mold blocks to the inside of thecasing over the spraying pipes.

5. A device according to claim 3 for the horizontal or nearly horizontalcasting, comprising a discharge pipe fed from said conduit, said casingincluding an upper cooling case divided into two chambers, a partitionbetween said chambers; spraying pipes in one of the chambers connectedto said discharge pipe; tubes welded to the partition and connectingsaid one chamber to the other chamber reaching down nearly to thesurface of the mold blocks and rising above the partition up to abovethe top edge of said discharge pipe, and a pipe connecting said otherchamber to said source.

6. A device according to claim 3, comprising a tube disposed in thecasing and connecting said casing to said source, and through which tubeair and vapor are sucked off due to the rarefied pressure.

8 A device as claimed in claim 7, said conduit supplying coolant firstto said cooler and thence to said spraying nozzles.

1. In a method for cooling, with the aid of a casing open at one side,the molding faces of mold blocks of a casting machine with a caterpillarmold, the steps comprising positioning the casing with the open sideclosely adjacent the molding faces where the molding faces are turnedaway from the casting, spraying through the open side a coolant againstthe molding faces while maintaining in the casing a rarefied airpressure such that due to the entry of air into the casing the coolantis restrained from escaping through any Space between the casing and themold blocks.
 2. A method according to claim 1, the coolant containing anemulsion of oil in water.
 3. A device, for use in spray cooling themolding faces of a caterpillar mold having mold blocks, comprising acasing connected to a source of rarefied air pressure and open towardsthe mold blocks and defining therewith a clearance of several tenths ofa millimeter, a conduit for supplying a coolant, said casing containingseveral spraying nozzles fed from said conduit and directed against themolding faces.
 4. A device according to claim 3 for the verticalcontinuous casting, comprising horizontal spraying pipes connected tosaid conduit and disposed one above the other and having each several ofsaid spraying nozzles, a deflector disposed over each spraying pipe fordrawing off the water pouring down the wall of the mold blocks to theinside of the casing over the spraying pipes.
 5. A device according toclaim 3 for the horizontal or nearly horizontal casting, comprising adischarge pipe fed from said conduit, said casing including an uppercooling case divided into two chambers, a partition between saidchambers; spraying pipes in one of the chambers connected to saiddischarge pipe; tubes welded to the partition and connecting said onechamber to the other chamber reaching down nearly to the surface of themold blocks and rising above the partition up to above the top edge ofsaid discharge pipe, and a pipe connecting said other chamber to saidsource.
 6. A device according to claim 3, comprising a tube disposed inthe casing and connecting said casing to said source, and through whichtube air and vapor are sucked off due to the rarefied pressure.
 7. Adevice as claimed in claim 3, a coolant reservoir, a cooler connected tosaid reservoir, a pump and said conduit supplying coolant to saidspraying nozzles.
 8. A device as claimed in claim 7, said conduitsupplying coolant first to said cooler and thence to said sprayingnozzles.